Manufacture of moistureproof paper packages



Nov. 27, 1928.

H. G. ECKSTEIN' MANUFACTURE OF MOISTURE-PROOF PAPER PACKAGES Filed April 2, 1925 Patented Nov. 27, 1928.

\UNITED STATES 1,692,822 PATENT} OFFICE.

HENRY G. ECKSTEIN, OF CHICAGO, ILLINOIS, ASBIGNOR TO THE CRACKER JACK 00.,

O1 CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

MANUFACTURE OI MOISTUREPROOF RA1ER RACKAGEE.

Application filed April 2,

The invention presented relates to the manufacture of parafiined paper packages for marketing candles, popcorn confection, and other food products that are readily affected and rendered unsalable by the absorption of small amounts of moisture.

It has been found that a paper package or wrapper containing parafiin wax only in its fibrous body or having only a slight coat or 0 surface film of wax that is easily cracked or broken or that leaves the fibers of the paper exposed, will not effectively prevent the passage of water vapor, but for efficient protection, the completed, filled ackagcs must have a substantial, unbroken lm or coat of paraifin wax extending throughout its walls and including its folds or joints. Such a protecting film cannot be provided if the folds of a paraflined paper wrapper are sealed by heat unless the wrapper originally has a very heavy surface coat suflici-ent to withstand the sealing heat which tends to disperse it. But the amount of paraffin coat that it is commercially practical to apply to a pa er sheet,

is limited, so that in sea ing, it is ifiicult to avoid overheating the wrapper. As set forth in my coending application which resulted in U. S. liietters Patent No. 1,451,145, dated April 10, 1923, to overcome the above-noted difficulties, the filled packages are enclosed in a waxed, heat-sealed wrapper and then immersed in melted wax to provide a protecting coat. But difiiculties have been encountered in providing a commercially practical method of dipping the packages which will insure a satisfactory protecting coat and employing the wax economically. Thus the best method heretofore proposed has been to completely immerse each package while gripped by a suitable holder and drain it with one corner or edge lowermost. But if the bath of wax is at a. sufficient high temperature to insure good drainage as the package is withdrawn from the bath, it will collect at the lower end of the package so that while this portion may receive a sufiieient coat,,the other portions of the package will not. Also the package holders become coated with wax and hence will not readily release so the packages and such holders or grippers frequently prevent the formation of a good protecting coat at the point of contact thereof with the package. I I

The present invention seeks to remedy the s above noted difliculties and, with these and 1928 Serial No. 629,375.

other objects in view as will presently apear, consists in the features of improvement iereina-fter set fort-h and more particularly pointed out in the appended claims.

In the accompanying drawings, which show the form 0 package to which the invention is particularly directed:

Fig. 1 is a perspective view of the inner wrapper or carton.

Fig. 2 1s a perspective view of the finished package.

Fig. 3 is a cross-sectional view thereof.

Fig. 4 is a view illustrating the manner of applying the finishing coat of parafiin.

The inner carton is preferably made of stiff paper board and is of the usual form, comprising an elongated. rectangular body 1 and the customary end flap 2 that are folded inwardly to enclose the contained goods. Preferably to prevent the confections, or other like oods from sticking to the carton, it is lig tly coated with paraffin and preferably also, it is heated and so dried to remove the greater portion of the contained moisture. The body of such a paper board carton will usually contain 5 or 6 percent ofmoisture dependent upon the atmospheric conditions and this amount of moisture is preferably reduced by drying to 2 or 3 percent just before the carton is filled and enclosed in the sealing wrapper, particularly if the goods to be packed readily absorb moisture.

The sealing wrapper 3 comprises a sheet of medium weight paper which is flexible so that it can be readily folded and which is sufliciently waxed to rovide a. heavy coat so that it can be quic l and easily sealed by the application of heat and pressure. Preferably manilla or bleached sulphite paper weighing between 20 to 35 pounds per standard ream before waxing is employed, and the paper carries suflicient wax-fr0m 10 to 35 pounds per reamto provide a substantial surface coat of wax on both sides of the sheet in addition to the wax in its body. The paraffined sealing wrapper is folded about the inner filled ackage and the overlappin side seam 4 of the wrapper and the usual olds 5 at the opposite ends of thepaekage are heated to partially melt the wax coat and are pressed 1nto snug engagement until the melted wax is cooled and set to tightly seal the side seam and end folds at all points.

The wrapped and sealed package is then dipped in a bath of melted paraflin for a few seconds, and after removal from the bath, it is cooled by exposure to the air or to a cooling air blast to set the vwax and rovide a uni form, continuous film over a parts of the package. Paraffin wax having a melting point of from 125 degrees to 145 degrees F. is employed and best results are obtained with wax 0 high melting point The bath should be-maintained at a temperature of about 15 to 20 degrees above the melting point of the wax, care being taken that the temperature be high enough to insure proper draining of excess wax and also to avoid excessive temperatures which would tend to open-the sealed folds of the packa e. Also to prevent the heat of the bath rom opening the sealed folds, the packages should be allowed to cool or be chilled if necessary to about room temperature after they are wrap ed and sealed y the application of heat and efore they are d1 ed in the bath.

0 rovidea uniform coat and particularly over t e folds 5 at the 0 posite ends of the package, the package is ipped as diagramma-tically indicated 1n Fig. 4. That is to say the lower portion of the package is dipped and slowly withdrawn from the bath in a substantially vertical direction while su orted by hand or by suitable rippers 6 w 1ch engage its upper undipped portion as shown at a and b in Fi 4. Also to avoid the formation of air bu bles as it is dipped and to insure proper draining of excess wax from the lowermost ed e as it is withdrawn from the bath, the pac cage is inclined or held at an angle to the vertical as shown. The time of immersion should vary with the temperatureof the bath, but with the temperatures indicated good results are obtained with an immersion of from 6 to 12 seconds. It is particularly desirable to slowly and quietly withdraw the package to permit the draining of excess wax and the settin of a substantial uniform coat on the di peg ortion as it is so withdrawn. Preferab y, a.- ter withdrawal, the package is promptly inverted as shown at c, Fig. 4, so that any further draining is back onto the package, and it is so held until the wax coat on the immersed ortion of the ackage is fully congealed. T e coated portlon of the package is then engaged by hand or by grippers, as shown at d, Fig. 4, and the opposite end portion is immersed, wlthdrawn and inverted in the same manner to provide a coat over the other half of the package and over its opposite end folds.

By thus treating the packa e a superficial coat or film to the extent of a out 1 to 2 pounds per 100 square feet Wlll be added, and, since the package has been previously enfolded and tightly sealed in a paraflin wrapper having a surface coat the added wax cannot penetrate or be absorbed by the walls 9f the package or seep in through 1ts folds or omts.

Nor will a film be formed which will be read- 1l y broken or chi ped off. Instead the additional wax will rmly unite or become fused or welded to the wax already on the wrapper, forming a heavy, superficial coat which will seal up all minute cracks and imperfections in the scaling wrapper and in particular will cover and repair any portions of its film which may have, been broken down by the heating and sealing of its folds. Again, since a previously waxed wra per is employed, the amount of wax adde by dipping can be more readily controlled and more effectively and economically employed to rovide the uniform film or coat than would pos sible if an unwaxed, glued or pasted wrapper were used. Furthermore, the two-stage method described of separately d1 pin portions of the package while it is eld liy an undipped portion, provides an effective uniform coat throughout and particularly where most needed, namely, over the folds at both ends; whereas it is quite diilicult to obtain satisfactory results by completely immersing the'package and its supportin means. In Fig. 3 of the drawing, the blue line 7 indicates the wax coat on the inner surface of the wra per and between its folds, and the heavier inc 8 is intended to indicate the film formed by its outer coat and the wax added thereto by the dipping o eration and which, as stated, extends over t e entire surface of the package includin its side seam and the endfolds. The overl apping portions of the coat provided by the two-stage method of dipping is indicated at 9 in Fig. 2.

The folding, sealing and dlpping operations ma be carried out in varlous ways but referabl v suitable machinery is employed.

n dipping the o posite end portions of the package it is pre erably immersed to such an extent that, as indicated, the coats overlap, but if the wrapper is originally rovided with a very heavy surface coat or fi m good results can be obtained by immersing t e o posite end portions to a less extent. Usual y, to protect the finished package from m ury it will be enclosed in an outer wrapper of pa r or paper board.

he procedure described provides a chea paper package of great efliciency in exclu ing air and water vapor from goods such as candied pop-corn that is highly sensitive to moisture. The package is also of value in marketing goods like marshmallows which become stale by losing moisture.

Obviously, the details may be varied without departure from the essentials of the invention as defined in the claims.

I claim as my invention:

'1. The method of moisture-proofing elongated, filled cartons,- which consists in enfolding the same in paper wrappers, tightly sealing the folds of the wrapper, then separately immersing the opposite end portions of each package while sustained by an undipped portion in a bath of melted paraflin, and, immediately after each immersion inverting the package to prevent excess drainage, substantially as described.

2. The method of moisture-proofing elongated, filled, paper cartons, which consists in enfolding the same in paper wrappers, tightly sealing the folds of the wrap-per and thereafter separately dipping the opposite end portions of the package in a bath of melted paraflin to weld on substantial protecting paraflin while the package is held by an undipped portion and thereby maintained in a position slightly inclined to the vertical, substantially as described.

4. The method of moimure-proofing filled, elongated cartons which consists in enfolding the same in paper wrappers, tightly sealing the folds of the wrappers, then, while the package is sustained by an undipped portion in a substantially vertical position, separately immersing the opposite end portions of the package of melted parafiin, and, after each immersion, slowly withdrawing, inverting, and cooling the packages to thereby form sligthly overlapping coats on each package, substantially as described.

5. The method of moisture-proofing elongated, filled, paper cartons, which consists in enfolding the package in a paper wrapper, tightly sealing the folds of the wrapper, and then, while the package is held by an-undipped portion, separately immersing in melted parafiin, slowly withdrawing and cooling the opposite end portions of the package to formsoverlapping coats, substantlally as described.

HENRY G. EOKSTEIN. 

